Conventionally, a communication apparatus may notify the position of a self-vehicle to other communication devices outside of the self-vehicle. The communication apparatus may periodically transmit at preset intervals the position information such as the current position of a self-vehicle, for example, as described in a patent document 1 (i.e., Japanese Patent Laid-Open No. JP-A-2006-23909).
Such a communication device may be configured to continue such a periodic transmission of the position information at the preset intervals to the other communication device after the stopping of the internal-combustion engine in the self-vehicle.
However, when the internal-combustion engine is stopped as mentioned above, the communication device will usually operate on electric power stored in the in-vehicle battery.
For this reason, when the communication device repeatedly transmits the position information even after the stopping of the internal-combustion engine, the consumption of electric power stored in the in-vehicle battery increases, which is undesirable. That is, for an in-vehicle communication device that is configured to transmit information after the stopping of the internal-combustion engine, it is necessary to control the consumption of electric power in the in-vehicle battery.